The shoemaker, or better alchemist, Vincenzo Cascariolo in the city of Bologna (Italy) passion was to find the "philosopher's stone," a way of turning common metals into Gold. About 1602, he
heated a mixture of powdered coal and heavy spar (Barium sulphate, BaSO4), spread it over an Iron bar, and let it cool. The Iron did not turn to gold. But when he took the bar in a dark room, he was astonished to see it glow!
Though the light eventually faded, Cascariolo found that repeated exposure to the sun "reanimated" the bar. The alchemist had discovered the phosphorescence of the combustion products of an heavy spar, but for him the process was shrouded in mystery. All across Italy, the new compound was known simply as lapis solaris, or "sun stone".
Later it would be called Stone of Bologna (cf. Phosphorus).

In 1772, the Swedish chemist Carl Wilhelm Scheele (1742-1786) noticed that pyrolusite (Braunstein, MnO2) contained embedded small crystals and recognized them as a new earth (oxide, BaO). Two years later Johan Gottlieb Gahn (1745-1818) in Falun, found the same oxide in heavy spar (in German "Schwerspat", BaSO4). Scheele called it Schwerspatherde (= earth of heavy spar). This "heavy earth" was named by Louis Bernard Guyton de Morveau (1737-1816) barote, later baryte, from the Greek βαρυς [barys] = heavy. The name was changed by Lavoisier to baryta.

The element was first isolated by Sir Humphry Davy. In his paper read for the Royal Society of London on 30 June 1808, he referred to the new alkaline earth metals in this way (note):

The element was also named Barytium (Berzelius 1812), but the shorter form Barium became the finale name. Clark had proposed to name the element Plutonium, after the god of Pluto, but his proposal it was not accepted.

Chemistianity 1873

KEYAN
BARIUM forms Salts of dense gravity,
It is a silvery white metal
That rapidly oxides in air; 'tis ductile,
And melts below redness, though not eas'ly vaporized.
Barium resembles Strontium and Calcium.